The University of Washington Center for Studies in Demography and Ecology (CSDE) requests support for an NICHD R24 Population Research Infrastructure Award. This request is based on the quality of the Center's research program and its impact on the field, the potential future contributions of the research program to population science, the quality and potential impact of the proposed infrastructure cores, the research competence of the key personnel, and the University of Washington' s commitment and research environment. For more than 50 years, CSDE's faculty affiliates have conducted research on demographic and related population science issues. The Center's 50 active program researchers are drawn from the fields of sociology, economics, anthropology, geography, statistics, public policy, and social welfare. Researchers currently are PIs or co-investigators on 95 externally funded grants, including 56 from NIH or NSF. They are engaged in a rich array of population research projects that revolve around five signature themes: Health and biodemography; Economic development and demographic change; Family demography; Inequality: Diversity and opportunity, and Demographic methods. The breadth of the Center's large, multi-disciplinary group of scholars fosters rigorous discussion of research and cross-fertilization of ideas that advance these themes. The recently established Center for Research on the Family further encourages interaction across disciplinary lines. The Center for Statistics and the Social Sciences provides opportunity to incorporate cutting-edge methodology into demographic research at CSDE. The active program researchers include 12 scientists from Western Washington University and the Seattle office of the Battelle Institute's Center for Public Health Research and Evaluation. Their research directly contributes to the signature themes and many collaborate with University researchers affiliated with CSDE. This application requests funds for five research support cores (administrative, computing, information, statistics, and a biodemography laboratory) and one developmental core to foster development of new population research themes and junior scientists.